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Listeria monocytogenes and listeriosis

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Presentation on theme: "Listeria monocytogenes and listeriosis"— Presentation transcript:

1 Listeria monocytogenes and listeriosis
Megan Antosik, RD

2 Agenda History Microbiology Related foods Infection Pathogenesis
At-Risk Populations Diagnosis & Treatment Outbreak History Current Outbreaks Prevention

3 Objectives After this presentation, audience members will be able to:
Identify at-risk populations for contracting Listeria monocytogenes. List 3 foods highly susceptible to contamination of Listeria monocytogenes Describe the clinical characteristics used to diagnose and identify listeriosis.

4 History Hayem (France, 1891) & Henle (Germany, 1893)
Hulphers (Sweden, 1911) assigned the name Bacillus hepatitis French clinicians preserved a diphtheroid isolated form of spinal fluid cultures of a patient with meningitis Bacterium monocytogenes, named for the monocytosis it produced in rabbits Gellin et al 1989

5 History Lord Joseph Lister (1925) – Listerella hepatolytica
Nyfeldt (1929) Listeria monocytogenes (1940) Gellin et al 1989

6 Listeria Seven species of Listeria Listeria monocytogenes
Listeria ivanovii Listeria seeligeria Listeria welshimeri Gellin et al 1989

7 Listeria monocytogenes
Facultative anaerobe ß-hemolytic Gram-positive Non-acid fast Non-sporulating linear rod Can grow at temperatures as low as 4°C Incubation period of 5-70 days Gellin et al 1989

8 L. monocytogenes Sixteen serotypes
Only 3 responsible for more than 90% of human disease Serotype 4b Serotype 1/2b Serotype 1/2a Gellin et al 1989

9 L. monocytogenes Ubiquitous in nature: Dust Soil Water Sewage
Decaying vegetation Animals can carry bacterium and transmit to food Gellin et al 1989

10 As a dietitian, what can we do?
How would you protect against an invader of this magnitude??

11 Susceptible Foods Ready-to-Eat (RTE) foods Raw foods
Hot dogs Delicatessen meats Soft cheeses Raw foods Meat Fruits Vegetables Unpasteurized foods Milk and milk products

12 +   Transmission Etiologic agent Reservoir Leads to…
Susceptible food Consumption of contaminated food

13 Listeriosis Severe infection
Consumption of foods contaminated by L. monocytogenes Symptoms Chills Fever Muscle aches Diarrhea Other GI symptoms

14 Pathogenesis &feature=related Intracellular pathogen Entry, growth, movement and spread in a macrophage Phagocytosis Actin filaments “comet tail” Bypasses humoral immune system Tilney et al 1989

15 Pathogenesis

16 At Risk? In the United States, an estimated 1,600 persons become seriously ill with listeriosis each year. Of these, 260 die. Older adults Pregnant women Newborns Immunocompromised General public

17 Manifestations Diagnosis of “invasive” listeriosis Symptoms include:
Headache Stiff neck Confusion Loss of balance Convulsions

18 Listeriosis in Older Adults and the Immunocompromised
Host-dependent Septicemia Meningitis Death Persons with AIDS: They are almost 300 times more likely to get listeriosis than people with normal immune systems.

19 Listeriosis in Pregnant Women
Twenty times more likely to get listeriosis. About one in six (17%) cases occurs during pregnancy Commonly experience mild “flu-like” symptoms Infections: Still birth Miscarriage Premature delivery Life-threatening Infection of the newborn

20 Diagnosis Blood Cerebrospinal fluid (CSF) Amniotic fluid
No stool or serological tests available

21 Treatment Most cases can spontaneously be cleared within 7 days
Otherwise - treated with IV antibiotics Ampicillin Bactrim

22 Outbreak History

23 Outbreak History

24 What can we do? Activate Listeria Initiative USDA FSIS & FDA
“Zero Tolerance” policy Initiate the Healthy People objective Achieve a 50% reduction in listeriosis incidence by 2010 2.5 cases per 1 million people Voetsch et al 2007

25 How do we evaluate efficacy?
Active surveillance studies Foodborne Disease Active Surveillance Network (FoodNet) Assess consumer practices Determine the burden of foodborne illness in the United States Monitor trends in the burden of specific foodborne illness over time Attribute the burden of foodborne illness to specific foods and settings Disseminate information that can lead to improvements in public health practice and the development of interventions to reduce the burden of foodborne illness. The network was established in July 1995 and is a collaborative program among CDC, 10 state health departments, the U.S. Department of Agriculture's Food Safety and Inspection Service (USDA-FSIS), and the Food and Drug Administration (FDA). FoodNet personnel located at state health departments regularly contact the clinical laboratories in Connecticut,Georgia, Maryland, Minnesota, New Mexico,Oregon, Tennessee and selected counties inCalifornia, Colorado, and New York to get reports of infections diagnosed in residents of these areas.  The surveillance area includes 15% of the United States population (46 million persons). FoodNet accomplishes its work through active surveillance; surveys of laboratories, physicians, and the general population; and population-based epidemiologic studies. Information from FoodNet is used to assess the impact of food safety initiatives on the burden of foodborne illness Voetsch et al 2007



28 What did we find? N=766 isolates from 1996-2003 670 hospitalizations
153 fatalities 122 pregnant-associated cases Voetsch et al 2007

29 Demographics

30 Crude Incidence

31 Did we achieve our goals?
Incidence of invasive listeriosis decreased by 24% Pregnancy-associated decreased by 37% Decrease of 23% in patients > 50 years old Crude incidence in 2003 was 3.1 cases per 1 million Voetsch et al 2007

32 Are we in the clear?

33 Cantaloupe Outbreak 2011 Jensen Farms 146 affected 28 states
4 different strains 30 deaths 1 miscarriage Outbreak has officially ended



36 What Went Wrong? Inspectors ignored federal regulators
FDA cited “serious design flaws” and “lack of awareness” Bio Food Safety Auditing gave Jensen Farms near perfect marks Jensen Farms did not have proper chlorine or anti- bacterial wash Improper equipment


38 As dietitians, what can we do?
Prevention methods Food Safety Cook foods thoroughly Prevent cross-contamination Buy pasteurized foods Proper sanitation Know where your food comes from Keep up-to-date on foodborne illness outbreaks Regulation of food safety policies

39 Questions? Don’t be afraid of food! Just play it safe!

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